Anyone have example temperature traces of hot water tanks left standing for 24+ hour

[Dan_Grey]

Tank manufacturers publish standing losses in terms of energy lost over 24 hours, but I’d like to see how that translates into temperature changes in tanks, and in the real world at that.

Does anyone have charts of DHW tank temperature where the tank has been heated to design temperature and left standing for 24 hours or more? Would be good if you could share the size of the tank too.

[Andre_K (André Kühne)]

This is a Sunex Fish 300l tank during my holidays last year. It wasn’t quite fully heated, but this should give you an idea. Temperature in the heating room is also included.

[Mld (Mark)]

This is the best I have for my 180L tank.

Note that I do not trust this temperature in the slightest, its just showing the temp at one particular point in the tank. Some times a single shower can cause it to drop 20C in a matter of minutes other times 5C.

I’ve had perfectly hot showers when the tank has been showing 15C

[JJC (John Cabra)]

Hi,

hope this helps

John

[Dan_Grey]

Hi John, how big is that tank? Thanks

[JJC (John Cabra)]

sorry should have said 180L

John

[sroof (Steve Roof)]

Here’s how my DHW tanked cooled down. The tank is a Rheem Proterra Performance Plus heat pump hybrid heater with a volume of 50 gallons (189 liters).
This is from December, when the ambient air temperature was 55°F (12.8°C)

And here in June when ambient air was 66°F (18.9°C)